Cement furnace



Aug 19 1924.

A. G. CROLL CEMENT FURNACE Filed 24, 1922 l N VEN TOR.

I one term or Patented Aug. 19, 1624.

umrsb STATES PATENT OFFICE.

ANDREW G. CROLL, OF ALLENTOWN, PENNSYLVANIA, ASSlIG-NOR TO THE ATLAS POBT- LAND CEMENT COMPANY, A CORPORATION OF PENNSYLVANIA.

CEMENT FURNACE.

Application filed August 24, 1922. Serial No. 583,987.

To (ZZZ whom it may concern:

Be it known that l, ANDREW G. Grow, a

supplied with current from a suitable source such as a battery-20, and the circuit for citizen of the United States, residin in Aleach motor includes a hand operated adlentown, county of Lehigh, and tate of Pennsylvania, have invented certain new and useful Improvements in Cement Furnaces, of which the following is a specification.

My invention relates to cement furnaces, and has for an object the provision of im- -proved means for supplying heat to such furnaces whereby the cost of operation may be materially reduced.

T will describe one form oil furnace embodying my invention, and will then point out the novel features thereof in the annexed claims.

The accompanying drawing is a view showing in side elevation, partly sectioned,

urnace embodying my invention.

Referring to the drawing, the furnace comprises a rotary lriln 1 mounted on rollers 2 and provided with a lining 3 of suitable heat-resisting material such as fire brick. Tn accordance with usual practice, this hiln is slowly rotated by means not shown in the drawing. The exit or lower end of the lriln 1 opens into a combustion chamber 4 provided with. a chute 5 by which the burned material is directed into a cooling cylinder 6 which is inclined as shown and is mounted on rollers '7 so that it may be rotated by mechanism not illustrated in the drawing.

Projecting into the combustion chamber d are two nozzles or burners '8 and 8, and opening into the rear ends or said burners are two pipes 11 and ll for supplying compressed air or steam thereto, said pipes being provided with hand valves 12 and 12 respectively, "for controlling the pressure at the will of the attendant. Leading into the burners 8 and 8 are fuel pipes 13 and 13 respectively, through which coal in pulverized or powdered form may be introduced lnto the burners so as to be blown by the compressed air or steam into chamber t and kiln 1. Coal is supplied to the fuel pipe 13 from a hopper 15 through a screw conveyer l7, driven by an electric motor l8, and coal is similarly supplied to fuel pipe 13 from a hopper 15' through a second screw conveyer 17 driven by a second electric motor 18 The two motors l8 and 18 are just-able rheosta t 19 or 19' where of each individual motor may be varied at will by the attendant.

The two hoppers 15 and 15 are supplied with anthracite coal and bituminous coal y the speed respectivel so that anthracite coal is iur- I nished to t e upper burner 8 and bituminous coal is furnished to the lower burner 8,

The preferred method of operating a furnace embodying my invention is as follows: To start the furnace, the attendant starts motor 18 which operates the conveyor 1'2 and so supplies bituminous coal to the lower burner 8 which coal is ignited in the usual way. As soon as this coal is thoroughly ignited, the attendant starts the other motor 18 which then operates conveyer 17 to supply anthracite coal to the upper burner 8. The burning bituminous coal ignites the anthracite coal, and, as soon as such ignition reduced to reduce the rate of supply oi bituminous coal to burner 8*. The rheostats l9 and 19 are then so adjusted as to secure the proper temperature and to produce clean and complete, combustion without smoke or soot. The combustion chamber a is preterably provided with a peep hole 4: to permit the attendant to observe the condition of the flames emitted by burners 8 and 8 l have found that the best results are secured by using approximately 40% ot anthracite and 60% of bituminous coal, although this proportion may be radically varied under diderent conditions and in furnaces of difierent designs and proportions. lit is necessary to supply only enough bituminous coal to keep the anthracite coal burning.

The most economical operation of a cement furnace is secured by burning anthracite coal, but it has heretofore been found impractical to use this kind of coal because ignition was too slow and the flame was ob soured by the smoke which collected in front of the peep-hole 4 due to the unburnt used. In case of emergency, it is, of course, possible to o erate the furnace on either anthracite or ituminous coal alone.

Although I have herein shown and described only one form of furnace embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departlng from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. The method of burning fuel for cement kilns and the like which consists in admitting into a common combustion zone from separate sources finely divided fuels mixed with air, such fuels com rising one of a higher degree of combusti ility such as bituminous coal and another of a lower degree of combustibility such as anthracite coal; and continuing combustion by so proportioning the relative amounts of such fuels admitted to the combustion zone that there is a sufficient proportion amount of the fuel such as bituminous more inflammable material to maintain the combustion of the less inflammable material and sufficient of the less inflammable material to supply a substantial portion of the heat.

2. The method of burning fuel for cement kilns and the like which comprises ad 4 mitting into a combustion zone from a ct, finely divided and relatively inflamma 1e coal admixed with air, igniting such fuel, heating the combustion zone with it, and thereafter admittin into the combustion zone from a jet positioned above such first-mentioned jet, finely divided fuel less inflammable than such first-mentioned fuel such as anthracite coal and reducing the amount of the firstmention'ed fuel admitted, so that more of the less inflammable fuel is burned than the more inflammable fuel that is burned.

ANDREW G. GROLL. Witnesses:

LEONARD Wesson, Ennns'r C. Cnms'rimn, 

